The present invention relates to a sound device including a helmet provided with a speaker therein. More specifically, it relates to a helmet having a speaker mounted in a lower end position thereof. A speaker provided in a helmet at its top portion and in the vicinity of the ears of the wearer and on both sides thereof, is well known. Since the shell of a helmet is close to the head in the top and side portion thereof, it is difficult to mount a speaker near the ears without forming protrusions on the external surface of the helmet shell. Therefore, it is practically difficult to mount the speaker in the side or top portion of the helmet for design reasons.
It is, therefore, an object of the present invention to provide a helmet provided with a speaker, taking advantage of a portion of the helmet which has previously been considered to be dead space, without affecting the external shape of the helmet shell.